Thermoplastic, high melting polyspiranes



United States Patent THERMOPLASTIC, HIGH MELTING POLYSPIRANES No Drawing. Filed June 10, 1957, Ser. No. 664,451

7 Claims. (Cl. 260-67) This invention relates to thermoplastic, high melting, crystalline condensation resins of the polyspirane type. More particularly, this invention relates to medium and higher molecular weight, linear condensates of dialdehydes or diketones with entaerythritol or mixtures of pentaerythritol and dipentaerythritol.

Previous attempts to react pentaerythritol with dialde-. hydes have resulted in materials of low molecular weight and lower melting ranges. These have been amorphous, often viscous materials which were either monomeric spiranes or at most contained only a few spirane units. These low molecular weight condensates usually have been obtained as crosslinked insoluble, non-crystalline materials.

An object of this invention is to produce soluble resinous condensates of dialdehydes or diketones with pentaerythritol, or Pentaerythritol and dipentaerythritol having a melting point of at least 200 C. A further object of this invention is to produce these resinous condensates having a molecular weight of at least 1,000.

These and other objects are attained by reacting (l) a material selected from the group consisting of (a) succinaldehyde glutaraldehyde, and mixtures thereof, (b) cyclopentanedial, cyclohexanedial, phthalic aldehydes and mixtures thereof, (c) mixtures of (a) and (b), (d) methyl and ethyl diacetals ofmalonaldehyde, succinaldehyde and glutaraldehyde, methyl and ethyl diketals of 2,4-pentanedione, 2,5-hexanedione and 2,6heptanedione; and'mixtures thereof. (e) methyl and ethyl substituted products of (a) and (d), and (2) a material taken from the group consisting of entaerythritol and mixtures of pentaerythritol with dipentaerythritol, containing up to 25% dipentaerythritol by weight of the mixture, in the presence of trace amounts of acidic catalyst in an inert liquid which is a solvent for at least one of the monomers.

This invention is illustrated but not limited by the following examples in which the parts are listed by weight:

(d) Distilled Water 2040 (2) Hydrogen lauryl sulfate 1.5

(a), (b), (c), and (d) were combined in'that order in a 3-necked round-bottomed glass flask equipped with a motor-driven stirrer and reflux condenser and heated to reflux while stirring. (Foam was minimized by the addition of a few drops of an anti-foaming agent.) The mixture was refluxed with stirring for 4.5 hours. At this 'ice time, 10 parts of 45 percent aqueous potassium hydroxide solution was added to the flask contents to terminate the reaction. Heating was discontinued, and the reaction mixture was permitted to stir for a further 10 minutes. Stirring was thereupon discontinued, and the reaction mixture was allowed to stand for 15 minutes. A major portion of the supernatant liquid then was decanted, and the rest of the reaction mixture was stirred into 10,000 parts of 1:1 by volume solution of methanol and water. This mixture was stirred for several minutes, then filtered through a Buchner funnel. The polymer collected was washed with excess 1:1 methanol-water solution until no more foam appeared in the washings. The Product finally was dried for 18 hours at 55 C. under 50 mm. pressure in a circulating air oven.

The product consists of a cream colored-to-light ,tan powder of very fine granular structure. It begins to decompose at about 270 C. but does not melt at 300 C. Heated on the end of a spatula over a Bunsen flame, it fuses at a very high but undetermined temperature, in? dicating thermoplasticity. This polymer has proved to be insoluble in carbon tetrachloride, acetone, benzene, glacial acetic acid, ethylene chloride, and acetonitrile. However, it swells slightly in pyridine and in dimethyl sulfoxide". It is soluble in cresylic acid, and other phenolic solvents. This material is the reaction product of equimolar proportions of dialdehyde and entaerythritol and has the following formula:

where x is aboutlO.

The molecular weight of the material in this example was 2,000. This was determined by standard procedure (end group analysis as described by Flory, J. Am. Chem. Soc. 58, 1877 (1936), and 61, 3334 (1939).

EXAMPLE II Preparation of poly(mal0ndiylidene Pentaerythritol) by transacetalization 7 Parts (a) Pentaerythritol 400 (b) Dry ber|7ene 2200 (c) Malonaldehyde, triethyl monomethyl diacetal 605 (d) p-Toluenesulfonic acid 10 (e) Cresylic acid 4000 L 2 hours, the theoretical amount of distillate was collected (1425 parts). The reaction mixture had turned from a deep yellow color to dark brown.

At this time, (e) was added to the reaction mixture along with a further 20 parts of (d). The reaction mixture was stirred at C. for 1% hours while all the benzene plus any traces of alcohol remaining in the reaction mixture were distilled under a slight vacuum justsufiicient to obtain a drop-wise rate of distillation. The distillate was collected in a flask cooled'in acetone Dry Ice, and the amount removed hereramounted to 1030 parts. The reaction mixture was cooled and then treated with sufficient aqueous 45 percent potassium hy droxide solution to make the resultingsolution yellow 2,969,464 v 3 4 color (complete neutralization). 60,000 parts of water EXAMPLE V were then added to the alkaline solution, while agitating vigorously, to precipitate the resin. The resulting solid Preparatmn of p 01y (g-malty lglutardly Mme pentaed wa collected by filtration through a Buchner funnel. 'ythritol) The solid was stirred into 10,000 parts of 1:1 methanol- T mixture f pentaerythritols used in water solution, thoroughly washed, and removed by ample III and 3-methylgtutafaldehyde Wel'e polymerized filtration. The product was dried at 55 C. and 50 mm. in equimolar proportions by direct condensation in a pressure for 18 hours. The final product was a cream manner Similar to Example I to give a White Solid of olored owder. When heated on th d f a t l fine particle size. This resin exhibited properties very over an open flame, it fused at a very high but undeterdifferent from its gluteraldehyde homologue Thus the mined temperature. It possessed the following physical Substituted resin Possessed a lower melting range. lower properties: solution viscosity, much higher molecular weight, and

solubility in a wider range of solvents (such as pyridine Thermoplastic a and ethylene chloride) than the latter. Finally, films 2 31 gi, than 300 (no decomposmon 5 cast from cresylic acid at 230 C. onto glass or aluminum were continuous and transparent but were much softer Average molecular welghtzswo than those from the unsubstituted resin.

Viscosity C.) (7 /&% cresylic acid solution)- 8 p R ti P1 P1 liolymer i ii$ 89.0 on O 81' 0 er, OX. 0 EXAMPLE m 20 Reaction Tlme o ii r IXIY I M ii wc. dr sy ue Aciii Preparation of p0ly(glutardiylidene pentaerythritol) from Temp' (Percent) (Avg) an 88:12 mixture of pentaerythritol and dipentaerythritol This preparation was similar to that of Example I. e 98 2054! 9.000 However, 423 parts of a mixture of pentaerythritols were I used, the mixture containing 88%, by weight of the The structural formula of the polymer produced was:

I" OCH\1 ECO\ OH: I OCH\ BC-O-HzC /CH:0\ CH3 1 C\ /HC-CHz-lH-CHz-C\ C\ C\ EC-CHPCHCH:- L o-og Hie-o o-c i Hio Hi0 car-'0 .iy

mixture, of monopentaerythritol and 12% of dipentaewhere b: is about 34 and y is about 5. rythritoL 35 EXAMPLE VI Polymer Vls- Reaction Reaction Polymer PolymenMP. cositytfl Per- A Polymerlzatlon. slmllar to x p IV was Tempr gigs aga i t fgfig tempted using glyoxal as the dialdehyde. This attempted (Op., 20 C.) condensation yielded only an oil. Polymerization attemptedwith the aid of dispersing agents also yielded an Reflux 5.0 92 %00(De%omp. 171.2 oily product,

egan a v 0 269 0.). Transacetalization was also used in an attempt to produce a thermoplastic, high melting polymer with The product, in appearance and in mostphysical propglyoxal. Equimolar proportions of the tetraethyl dierties, was comparable to the resin previously prepared acet'al of glyoxal and an 88:12 mixture, by weight, of from 100 Percent pentaerythritol in Example the pentaerythritols were mixed in benzene and reacted e the Viscosity of the cresylic acid Solution was according to the method of Example III. A reaction signtficatty higher than that of the resin Produced in time of 16 hours was required to react 64% of the mono- .Exanlple I and fi cast from solution 9 glass iners. The molecular weight of the final product was aluminum at 300 C. possessed better continuity, trans- 200 and the viscosity of a 71/2% cresylic acid solution parency, flexibility and adhesion. was 400 c As little as 12 percent dipentaerythritol substituted for monopentaerythritol in the resin yielded an improvement ,Read reported In the Journal the chemtcal in film formation and adhesion with correspondingly little 9 m 2 that hea'tmg rentaerythrlwl change in the original melting point and solubility char- Wlth glyoxal 111 50% aqueous Sulfllfle eeld Produced a acteristics, white powder insoluble in all the ordinary solvents as The polymer produced had the following structural well as in boiling nitrobenzene or phenol. Such informula:

L o-c Hie-o o-cg mi CH: CHr-O y OH H where xis about 9 and y is about 1. solubility is indicative that the materials produced were EXAMPLE Iv cross linked rather than linear.

The reaction of Example III was carried out in a EXAMPLE VII similar manner, however, the dispensing agent was An attempt to polymerize pentaerythritol and a-hyomitted. A 4-hour reaction time resulted in a 95% condroxy adipaldehyde by the condensation method deversion. The resin had a molecular weight of 1200, a scribedfor glutaraldehyde in Example I gave no polymer. However, this result can be explained quite logimelting point of 208 C. and a 7l/2% solution in cresylic I y p H cally. By analogy with the structure of sugars, u-hyacid had a viscosity of 60 op.

droxy adipaldehyde probably exists in actual fact as the following cyclic hemiacetal.

- I OH In such a form, one of its two aldehyde groups is probably not free to react here. This explanation is strongly supported by J. Reads findings (ibid.) which indicate that neither salicylaldehyde nor glucose react with pentaerythritol in the presence of aqueous sulfuric acid. He concludes that a hydroxyl group in a neighboring position to the aldehyde group exerts an inhibitory influence on the reactions of the aldehyde group. The above result supports this conclusion. The inhibition of the a-hydroxy adipaldehyde in these condensation reactions may be due to the aldehyde group being tied up by internal hydrogen bonding or by the formation of a hemiacetal structure.

EXAMPLE VIII? Attempts to polymerize pentaerythritol and 2,5-hexanedione in aqueous solution according to the methods of Examples I and IV were unsuccessful. Thus ketones appear to be reluctant to condense directly with pentaerythritol under these conditions.

EXAMPLE IX Preparation of poly(2,5-hexanediylidene pentaerythritol) EXAMPLE X A copolymer of equimolar parts of glutaraldehyde and S-methyl glutaraldehyde with the 88: 12 mixture of pentaerythritols was prepared by the method of Example III. A reaction time of 5 hours gave a 94% conversion, the polymer formed having a molecular weight of 5,500 and melting at above 300 C. v

A similar attempt to form a copolymer with 30 (mole) percent of glyoxal and 70 (mole) percent of glutaraldehyde as the dialdehyde resulted in a polymer yield of 82% after 6 hours. The viscosity of a 7 /2% solution in cresylic acid was 82.0 cp. The viscosity of the equivalent glutaraldehyde polymer produced in Example III was. much higher. This reaction was slow. The transacetalization with glyoxal diacetal in Example VI was even slower producing a very low molecular weight material. These experiments appear to indicate that the glyoxal has an inhibiting effect on the rate or extent of polymerization.

EXAMPLE XI The reaction of 120 parts of the 88:12 mixture of pentaerythritols with 83 parts of glutaraldehyde in 565 parts of water (without the use of any dispersing agent) "in the, presence of 2 parts of oxalic acid resulted in a polymer with a molecular weight of over 1100 and a melting point above 200 C. This reaction was terminated without neutralization but merely by the addition of large amounts of water. The reaction time was 2 hrs. and the yield 97%. 7.4 parts oxalic acid gave similar results, as did 4 parts formic acid. However, the yield from the formic acid was only 85% after 2 hours. A 97% yield was obtained with 7 parts formic acid after 4 hours. In all cases solubility in cresylic acid joccurred readily.

EXAMPLE XII.

Similar reactions using a mixture of pentaerythritols containing 30 parts of monopentaerythritol and 10' parts dipentaerythritol, 26 parts glutaraldehyde and 188 parts water in the presence of 0.7 part of oxalic acid yielded the polymers of'this invention. However, the use of a pentaerythritol mix containing 50% dipentaerythritol with p-toluenesulfonic acid as catalyst, and the use of a mix containing 95% dipentaerythritol with phosphoric acid as the catalyst yielded non-linear polymers insoluble in boiling cresylic acid. The polymers of this invention are unique in that they are high melting, linear, thermoplastic materials of medium to high molecular weight formed by reacting dialdehydes, diacetals of dialdehydes, or diketals of diketones with about equimolar amounts of pentaerythritol or mixtures of pentaerythritol with dipentaerythritol. These polymers may be used in surface coating compositions and films may be cast from solutions at 200-300'C. They may be formed into solid products by molding or extrusion, alone or in combination with other resins. Linear polyspiranes may be used in their uncured form or they may be heat cured with a variety of cross-linking materials such 'as traces of inorganic acid, phenolic resins, epoxies, isocyanates, anhydrides, esters,'polyvalent ions and others. These polymers are especially desirable in applications where high temperature resistance is needed along with films possessing good adhesion. The electrical insulating properties of these resins are outstanding. Although the materials produced were generally cream to tan colored, carefully controlled conditions have indicated that clear white products are obtainable.

In general, various aliphatic or cyclic dialdehydes may possibly be used to prepare the polymers of this invention. 'However, aliphatic dialdehydes of 6-7 carbons tend to cyclize and may therefore react unfavorably. In addition, polyspiranes with melting points of at least 200 C. have not been obtainable with aliphatic dialdehydes of 6 carbons or more. Glyoxal does not produce the polymers desired. The aliphatic dialdehydes used to prepare these polymers are therefore limited to malonal dehyde, succinaldehyde and glutaraldehyde, and methyl and ethyl substituted products thereof and mixtures thereof.

Cyclic dialdehydes may also be used. Cyclopentanedial, cyclohexanedial and ortho, meta and para phthalic aldehydes will produce the desired thermoplastic polymers having a melting point above 200 C. and amolecular weight of at least 1,000. Naphthylene dialdehydes and other polycyclic dialdehydes should also produce satisfactory products. Alkyl substituted products of cyclic dialdehydes tend to produce polymers having lower melting points. Saturated cyclic dialdehydes tend toward self condensation and are therefore preferably reacted in an aqueous system. The solubility of the cy- V clic monomers at the reflux temperature of an aqueous system is sufiicient to enable the polymerization to procede rapidly. Diketones do not react readily with pentaerythritol. by themselves and are therefore used in the diketal form to produce these polymers by transketalization. The ketones used are limited to 2,4-pentanedione, 2,5-hexanedione and 2,6-heptanedione in order to insure producing polymerswith melting points of at least 200 C. V The polymers may be prepared similarly by transacetalization from dialdehydes in diacetal form. Mixtures of diacetals and diketals may be used. Some cyclic diketones may also be used but not all will produce high melting polymers. As in the case of the dialdehydes, side chain alkyl groups tend to decrease the melting point and crystallinity of the polymers formed. However, polymers with a melting point of at least 200 C. can be obtained from some methyl and ethyl substituted aliphatic diketones.

The formation of these resins is prevented if the direact readily inthe condensation. The solubility of penaldehydes or diketon'es contain various interfering reactaerythritol in benzene or of terephthalaldehyde in water tive constituents such as active hydrogen atoms adjacent is limited even at reflux but as the initial resin formed to the carbonyl groups. Any existing functional groups precipitates out of the system enough of the relatively preferentially producing a different reaction must be insoluble monomer is dissolved or at least wet by the avoided. Strong interference to the normal reaction is system to produce a fairly rapid reaction. The initial produced by the presence of hydroxyl groups adjacent low molecular weight condensates produced are soluble to the carbonyl group. Materials, such as, a-hydfOXy in the system in which the monomer or monomers are aldehydes and o-liydroxybenzaldehydes do not form the dissolved. The resins are precipitated out of solution as polymers of this invention under the conditions described. 10 higher molecular weights are attained. This molecular Materials such as malonaldehyde, adipaldehyde or pimel- Weight Varies depending on the Speeifie reactants and the aldehyde, which are decomposed or self-condensing unreaction conditions but these molecular weights are not der certain conditions are not usable in an aqueous polyn s rily the maximum obtainable since the P y merization system. Malonaldehyde is therefore used in chains Will Continue to g Somewhat as long as y the form of an acetal derivative. are swelled by the monomer solvent system.

Polymers have been produced with the aforementioned W molecular weights above about 2,000 re ir d dicarbonyl compounds and pentaerythritol as well as with in all aqueous System it is necessary to add about mixtures of pentaerythritol containing up to 95%, by y Weight of the monomers, of a dispersing agent weight of the mixture, of dipentaerythritol. The use of c s Sodium la ryl Sulfate to the system. These dissome dipentaerythritol is highly desirable in that the film Persarlts y be alliehie, cationic 0T hon-ionic Surface forming ability and adhesion of the films formed is better tension depressants Wetting agents, Such as alkali metal than that of polymers made with pentaerythritol alone. Salts of g Chain fatty acids, for example, Potassium However, the dipentaerythritol is limited to or less steerhigher fatty alcohol sulfates. for p of the mixture in order to insure obtaining materials havdium lauryl sulfate; polyethylene oxides, such as ethylene ing a melting point of at least 200 C, Larger am unt 25 oxide derivatives of etherified or esterified polyhydroxy of 'dipentaerythritol tend to decrease the crystallinity of mp alkYlPhellOXY-POlYethYOXYethaIIOlS; quaterthe resins produced and, under the conditions described, n ry mmonium derivat ves of alkyds 0r pyridine betaine may increase the chance of forming a brittle, insoluble, types made from b ends of fatty acids; and the like. cross-linked material. Under milder conditions, includ- Resins made for electrical insulating purposes are prefer: ing the use of weaker acids, it is possible to produce nonably prepared Without the aid Of dispersing ag nts in crosslinked polymers from mixtures containing as much order to attain a maximum of insulating effectiveness. as 25-95% dipentaerythritol. The use of some dipen- These reactions are run at or about reflux temperatures taerythritol appears to cause a slower reaction in the in Order to achieve maximum m l ular W ights and a processes described than with pentaerythritol alone. The reasonable conversion time. If an inert organic solvent presence of other polypentaerythritols such as tripentais used, a boiling point of about 80 C. or higher is preerythritol will cause some cross-linking even under careferred since lower temperatures tend to produce products fully controlled conditions. The tendency of an excess with molecular weights below 1,000. Solvents used for of certain dialdehydes to cause some cross-linking of the the transacetalization or transketalization systems should, polymer chains is diminished by using a slight molar in addition to the desirability of boiling at about 80 C. excess of pentaerythritol in the reaction. or above, possess the characteristic of forming a lower The polymers of this invention produced with pentaboiling azeotrope with the alcohol produced by the reacerythritol have the following general formula: tion. Benzene cyclohexane, methylcyclohexane, n-hep- 0 O H C 0 tane are among the solvents possessing the desired require.- 1 ments. The azeotrope is removed by distillation during C R o R\CR'- the process in order to drive the reaction to completion. L L Of course, a high boiling solvent which allows the re moval of the alcohols by distillation without any signifiwhere R is taken from the group consisting of H and cant loss of monomers or solvent may also be used. The CH R is taken from the group consisting of aliphatic addition of a solvent for the polymers produced after a hydrocarbons of l-3 carbon atoms and cyclic hydrocarmajor amount of the transacetalization or ketalization bons of 5 and 6 carbon atoms, and x is an integer from has taken place will produce higher molecular weight 5-50. polymers. These reactions may be conducted under The polymers of this invention produced with mixtures pressure it higher temperatures are desired. An aqueous of pentaerythritols have the following general formula: reaction conducted at 75 C. yields a molecular weight where R is taken from the group consisting of H and equal to'only about A of that obtained at reflux tem- CH R' is taken from the group consisting of aliphatic perature. Higher temperatures not only tend to increase hydrocarbons of 1-3 carbon atoms and cyclic hydrocarthe molecular weight produced but also decrease the bons of 5 and 6 carbon atoms, x plus y is equal to an reaction time. integer from 5 to 50 and y is an integer equal to no more The reaction may be terminated by neutralizing the than 25% of x plus y. catalyst with alkaline reagents, by cooling the system or The high melting polyspirane resins of this invention by removing the precipitated product. The product may be formed in an inert liquid which is a solvent for should be washed carefully to remove as much contamiat least one of the monomers. An inert liquid is one nating catalyst as possible since acid catalysts are potenwhich does not interfere with the polymerization reaction tial crosslinking agents when drying with heat. The and may be water or an inert organic solvent. Faster presence of any other contaminating or reacting materials reactions are possible if both monomers are soluble. One during polymerization is, of course, to be avoided. Other of the monomers may be only slightly soluble and yet 7 hydroxyl containing materials, such as cellulose, com- 2,963,464 petmg with the pentaerythritols for condensation with the dipentaerythritol containing from about 12 to 25% didlaldehydes will affect the structure of the polymers pentaerythritol by weight of the mixture, which resinshavformed. ing the general formula:

- OH OH The concentration of the monomers in the solution or where R is taken from the group consisting of H and CH dispersion systems is not generally critical. The preferred R is taken from the group consisting of 1-4 carbon atoms, concentration is about 10-100 parts of monomer to about x-l-y is equal to an integer from 5-50 and the ratio x/y is 100 parts of solvent. Extremely dilute systems (such as 15 a number from 11.8 to 6.5 respectively, said resins having 0.25 part monomer to 100 parts solvent) will not proa molecular weight of about 1000 to 10,000 and a meltduce these linear polymers and concentrated systems such ing point of at least 200 C. as about 180 parts or more of monomer per 100 parts 2. Solid linear thermoplastic resins which are the polysolvent) may tend to produce reactions between some meric reaction product under acidic conditions of about of the dialdehyde molecules. 7 equimolar amounts of glutaraldehyde with mixtures of As catalysts, trace amounts of any of the common strong pentaerythritol and dipentaerythritol containing from acids are acceptable. Sulfuric, hydrochloric, p-tolueneabout 12 to dipentaerythritol by weight of the mixsulfomc, PhOSPhOIlC, hydrogen lauryl sulfate, maleic, ture, which resins having the general formula:

o-om Hie-0 0-0H1 H2C-OCH2 GHQ-O a L o-oH. Bio-o 0-06 (3H2 cg 0112-0 .iy

OH H

oxalic, formic acids and their acidic derivatives have been where x-l-y is equal to an integer from 5-50 and the ratio used. The preferred concentration of acids used ranges x/y is a number from 11.8 to 6.5 respectively, said resins from 0.1 to 1.0% by weight of the monomers, dependhaving a molecular weight of about 1000 to 10,000 and a. ing on the strength of the acids used. Up to about 5% melting point of at least 200 C.

may be used satisfactorily. Of course, the use of larger 3. Solid linear thermoplastic resins which are the polyamounts of acid increases the possibility of contaminating meric reaction product under acidic conditions of about the product with adsorbed and occluded acid. Excessive equimolar amounts of 3-methylglutaraldehyde with mixconcentrations-of acids will tend to produce cross-linked tures of pentaerythritol and dipentaerythritol containing materials even when drying at moderate temperatures. from about 12 to 25 dipentaerythritol by weight of the The high melting polymers of this invention are readily mixture, which resins having the general formula:

| o{ o no-orn-on-on of 0 0 nc-cni-on-onrsoluble in cresylic acid and related alkyl phenols. Howwhere x+y is equal to an integer from 5-50 and the ratio evera limited number of other materials will dissolve and x/y is a number from 11.8 to 6.5 respectively, said resins retain these polymers in solution with the aid of heat. having a molecular weight of about 1000 to 10,000 and a These include dirnethyl sulfoxide, 2-pyrolidone, tricresyl melting point of at least 200 C.

phosphite, furfuryl alcohol, a 1:1 mixture, by volume, of 4. A process for preparing linear thermoplastic polyfurfuryl alcohol with chlorobenzene, and certain liquid spiranes having a molecular weight of about 1000 to about epoxy resins. 10,000 and a melting point of at least 200 C., said process The linearity and crystallinity of these resins is shown comprising mixing about equimolar amounts of (l) a diby their solubility behavior and high melting points. aldehyde taken from the group consisting of at least one Many of these materials may be melted and remelted aliphatic dialdehyde containing 3-5 carbon atoms, 3- without adverse effect. However, relatively slow heating methylglutaraldehyde and mixtures thereof, (2) mixtures to temperatures near their melting point may cause crossof pentaerythritol with dipentaerythritol containing from linking and the resulting material produced is infusible about 12 to 25% dipentaerythritol by weight of the mixand insoluble. ture; in an inert liquid which is a solvent for at least one Linear polyspiranes have been produced having molecuof the monomers, the total amount of monomer being lar weights of from 1,000 to 10,000 with melting points from about 10 to 100 parts monomer per 100 parts of inert above 200' C. Polymers with melting points above 300 liquid, stirring and heating at about 75 to 100 C. in the C. can be produced from unsubstituted dialdehydes havpresence of 0.1 to 1% by weight of the monomers of ing 3-4 carbon atoms. It has been found that alkyl and acidic catalyst, removing the precipitate formed, washing aryl substitutents in the dialdehydes and diketones yield and drying.

polyspiranes of higher molecular weights. 5. A process as in claim 4 wherein the inert liquid is What is claimed is: 1 water.

1. Solid linear thermoplastic resins which are the poly- 6. A process as in claim 5 wherein about 05-10% by meric reaction product under acidic conditions of about weight of the monomers, of a dispersing agent taken from equimolar amounts of (1) a dialdehyde taken from the the group consisting of anionic, cationic and non-ionic group consisting of at least one aliphatic dialdehyde consurface tension depressants is included in the water. taining 3-5 carbon atoms, 3-methylglutaraldehyde and 7. A process for preparing linear thermoplastic polymixtures thereof with (2) mixtures of pentaerythritol with spiranes having a molecular weight of about 1,000 to about 11 a 10,000 and a melting point of at 1east200 C., said process comprising dissolving about equimolar amounts of (1) a dialdehyde taken from the group consisting of at least one aliphatic dialdehyde containing 3-5 carbon atoms, 3- methylglutaraldehyde and mixtures thereof, (2) mixtures of pentaerythritol with dipentaerythritol containing from about 12 to 25% dipentaerythritol by wei ht of the mixture; in an inert organic solvent for the monomers with a boiling point of at least 80 C., stirring and heating at reflux in the presence of 0.1 to 1% by weight of the mono- 10 mass;

s 12. .t mers of acidic catalyst, until polyspiranes having a molecular weight of at least about 1000' are produced, precipitating the polyspirane, washing and drying.

References Cited in the file of this patent UNITED STATES PATENTS 2,739,972 Abbott et a1. Mar. 27, 1956 2,785,996 Kress Mar. 19, 1957 2,889,290 Capps June 2, 1959 

1. SOLID LINEAR THERMOPLASTIC RESINS WHICH ARE THE POLYMERIC REACTION PRODUCT UNDER ACIDIC CONDITIONS OF ABOUT EQUIMOLAR AMOUNTS OF (1) A DIALDEHYDE TAKEN FROM THE GROUP CONSISTING OF AT LEAST ONE ALIPHATIC DIALDEHYDE CONTAINING 3-5 CARBON ATOMS, 3-METHYLGLUTARALDEHYDE AND MIXTURES THEREOF WITH (2) MIXTURES OF PENTAERYTHRITOL WITH DIPENTAERYTHRITOL CONTAINING FROM ABOUT 12 TO 25% DIPENTAERYTHRITOL BY WEIGHT OF THE MIXTURE, WHICH RESINS HAVING THE GENERAL FORMULA: 